The field of the invention is glow plugs and the invention relates more particularly to a high performance glow plug for use in state of the art engines, particularly in model car engines.
Internal combustion model cars have been refined to an extent that tethered model cars can substantially exceed 200 mph. In such extreme environments the glow plugs are heated to a temperature where conventional glow plugs will leak and fail. Various improvements in glow plug construction have been made. One such improvement is shown in U.S. Pat. No. 6,346,688 having the same applicant as the present application. This patent is incorporated by reference herein.
Temperatures at the lower end of a glow plug can reach in excess of 1000° F. The combination of the pressure in the cylinder of the engine and the high temperature of the lower end of the glow plug can result in the formation of leaks which reduce the compression within the cylinder which is highly detrimental to the performance of the engine. A better seal against leaking can result when the crimping downward force is increased. However, the amount of force is limited by the strength of the plug body. Increased crimping force can deform the base of the plug and cause it to deform outwardly. Various attempts at improving the crimping at the top of the glow plug have reduced, but not eliminated, the problem. A better seal against leaking can result when the crimping downward force is increased. However, the amount of force is limited by the strength of the plug body. Increased crimping force can form the base of the plug and cause it to move outwardly.